Smartphones. Ipods. Nintendo Wii. Digital cameras. Your kids might know how to operate these gadgets and gizmos better than you do. Technology changes all the time. Devices that monitor heat stress in dairy cattle are evolving, too. These tools could make the ordinary rectal thermometer look as outdated as an eight-track tape.
Here’s a look at three technologies that monitor the body temperature of cows and their environment. Some of the research is still in the early stages of development, but has implication for on-farm use.
Temperature or data loggers store information such as ambient temperature and relative humidity, which can then be used to monitor temperature fluctuations in the cow’s environment.
One such device, called the Thermochron iButton, is a computer chip enclosed in a tiny stainless steel case. According to Maxim Integrated Products, the iButton’s manufacturer, it can be mounted almost anywhere. On a dairy, this could include gates or support posts in the barn. Researchers also have placed iButtons in the ear canal of cattle.
In a Texas A&M study, researchers evaluated the accuracy of iButtons. They wanted to find out if these data loggers were less accurate as they aged or when they were used over a range of temperatures. They tested the iButtons in a thermostatically controlled water bath and compared the temperature readings to that measured by a calibrated thermometer. Older iButtons were not as accurate as new ones. However, accuracy of the iButtons, regardless of age, improved as the water temperature increased.
Data-logging devices are not limited to the research world. In some cases, they have already found application on-farm, such as in the holding pen.
Another data logger, dubbed the “HOBO,” also measures and records temperature. It is commonly used in the food industry. Researchers have placed it intravaginally in the cow to monitor fluctuations in her body temperature.
Data from both the HOBO and iButton can be uploaded to a computer for further analysis.
Automated temperature-monitoring systems
Automated temperature-monitoring systems utilize an internal bolus and a panel reader to monitor body temperature.
Researchers at Purdue University used a bolus equipped with a temperature sensor to monitor the body temperature of lactating cows. The system includes a stationary panel reader and data-collection software. When a cow walks by the panel, it “reads” the bolus inside her reticulum. Software collects the cow’s reticular temperature.
In one experiment, the researchers used the system to assess the impact of temperature-humidity index and other factors on the cows’ reticular temperatures. Temperature-humidity index is one indicator of heat stress in dairy cows.
There was some variation in the temperature readings collected by the system. The variation increased as the temperature-humidity index increased. In another study, water intake by the cows also affected the temperature readings.
Bella Health Systems recently acquired the license for the technology and is modifying it to make it more flexible for use on-farm, says Mike Schutz, associate professor and dairy extension specialist at Purdue. This type of temperature-monitoring system also is used for early detection of sick cows.
Some research has been done in cattle to measure the thermal temperature of the muzzle.
Researchers at Mississippi State University captured thermal images of the muzzles of beef heifers using an infrared camera. Then, they highlighted quadrants of the muzzle to determine the correlation between muzzle temperature and rectal temperature. Certain quadrants were more highly correlated to rectal temperature than others. Their results were reported last summer at the joint annual meeting of the American Society of Animal Science and the American Dairy Science Association. They say the technology has potential as a tool for early detection of stress in cattle.
Researchers at Mississippi State University and Texas A&M also used an infrared camera to measure the eye temperature of beef cattle. These types of images also can be used to assess cattle body temperature. So far, researchers are assessing the impact of environmental factors on eye temperature. In one study, they found that changes in ambient temperature influenced thermal images of the eye, which must be considered when using the images to measure body temperature.
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